The present invention relates generally to disc brake assemblies for vehicles, and more specifically, to a brake protection device having vanes arranged to provide increased airflow to a disc brake rotor while preventing the entry of dirt and water into the brake mechanism.
It is known to provide stamped metal shield components for brake assemblies in vehicles to protect the brake components from water, dust and other potentially harmful foreign particles. Generally, a sheet metal stamping is attached to the axle adjacent the brake rotor with the shield extending radially to a point adjacent the rim of the vehicle wheel and provided with openings through which the brake actuating mechanism and the like may be provided.
FIG. 1 illustrates a typical splash shield 10. Generally, the splash shield 10 includes a central xe2x80x9chat portionxe2x80x9d 12 or attachment portion and an annular shield portion 14. A plurality of bolts 16 fix the xe2x80x9chat portionxe2x80x9d 12, a disc-shaped attachment portion with a depending annular sidewall or extending portion 18, to an axle housing (not shown) located at the back of the shield 10, adjacent an axle 20 of the vehicle. The shield portion 14 is a flange-like radial extension of the sidewall 18. In practice, while providing an important shielding benefit, shields tend to discourage free flow of air about the brake surfaces and thus, tend to trap heat in the brake components.
Heat is generated in the brake rotor as the kinetic energy of the moving vehicle is converted to heat energy through the frictional interface between brake pads forcibly applied against the brake rotor. One effect of overheating of brake components is warping or coning of the brake rotor. This distortion of the rotor may cause increased pedal travel and effort, or roughness felt in the brake pedal under moderate braking. Another result of overheating is a reduction of frictional properties at the brake interface above a predetermined temperature. This may result in longer stopping distances, especially after repetitive heavy stopping. Preventing the rubbing surfaces from exceeding a predetermined temperature also provides greater durability for the brake rotor and pads.
Finally, heat management has been one of the primary obstacles to designing a successful brake rotor constructed from a lower density material than case iron steel. Due to the increased thermal conductivity of the lower density materials, excessive heat may be conducted into the hub assembly of the vehicle to which the brake rotor is attached. This transfer of excess heat to other parts of the brake and hub assembly may negatively impact braking performance and may negatively impact the longevity of the brake and hub assembly.
To reduce heat management problems, partial splash shields and shields with large or multiple vent openings have been used to address the problem of reduced heat dissipation when using a shield, but these methods have resulted in compromised performance of the shield in preventing contamination of the brake components.
It would be desirable to provide a splash shield having effective shielding properties coupled with a way to promote heat transfer from a corresponding brake rotor.
One aspect of the present invention provides a splash shield for a vehicle wheel disc brake assembly. Each wheel disc brake assembly includes a brake rotor having an outer brake surface and a splash shield. The splash shield includes a central attachment portion. Extending from the central attachment portion is a flange-shaped shield portion. The shield portion has an outer surface with a plurality of generally radially extending vanes formed on the outer surface of the shield portion, the vanes being positioned adjacent the inner brake surface of the brake rotor when the splash shield is mounted to the vehicle.
In other aspects of the present invention the splash shield includes vanes that may extend at about a 45-degree angle from the radial direction. The vanes may have a longitudinal arcuate shape. The arcuate shape of the vanes may have a radius of about 6-10 centimeters. Preferably, the arcuate shape of the vanes may be a radius of about 8 centimeters. The arcuate shape of the vanes may be a radius of about 7.7 centimeters.
In further aspects of the invention, the splash shield may further include a sidewall portion depending from the central disc portion at a first edge, the sidewall portion extending and connecting to the shield portion at a second edge. A plurality of vents may be formed in the sidewall portion of the splash shield. A plurality of tabs having an edge attached to the sidewall portion adjacent the second edge of the sidewall portion and extending inwardly may be formed in the sidewall portion, each tab extending over an associated vent.
In further aspects of the invention, the splash shield may include vanes that extend from the outer surface of the shield surface a width of about 10 mm. The vanes may extend in a direction normal to the outer surface of the shield surface or may be inclined with respect to the outer surface of the shield surface. The vanes may have an arcuate shape extending across the width of the vane.
An aspect of the present invention includes a method of cooling a disc brake rotor. The method includes positioning a plurality of vanes of a splash shield adjacent the disc brake rotor and directing air along the vanes to cool the rotor. Further aspects of the method include disrupting concentric airflow patterns created by the rotor, flowing air through a plurality of vents formed in the splash shield and preventing foreign material from entering a space between the disc brake rotor and the splash shield.
An aspect of the present invention includes a system for cooling a disc brake rotor including means for directing air along a radial span of the disc brake rotor to cool the disc brake rotor, means for increasing air flow through the air directing means and means of preventing foreign material from accessing a space between the air directing means and the disc brake rotor.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.